Exclusive: Syria strike due in days, West tells opposition - sources

AMMAN (Reuters) - Western powers have told the Syrian opposition to expect a strike against President Bashar al-Assad's forces within days, according to sources who attended a meeting between envoys and the Syrian National Coalition in Istanbul.

"The opposition was told in clear terms that action to deter further use of chemical weapons by the Assad regime could come as early as in the next few days, and that they should still prepare for peace talks at Geneva," one of the sources who was at the meeting on Monday told Reuters.

The meeting at a hotel in downtown Istanbul was between senior figures of the Syrian National Coalition, including its president, Ahmad Jarba, and envoys from 11 core "Friends of Syria" alliance members, including Robert Ford, the former U.S. ambassador to Syria who is now Washington's pointman with the opposition, the sources said.

Facing Russian and Chinese opposition that could dampen prospects for proposed peace talks in Geneva, Assad's foes have vowed to punish a poison gas attack in some rebel-held districts of Damascus on August 21 that killed hundreds of people.

Another source said Ford told Jarba at the gathering that the coalition should "expect appropriate action to deter more use of chemical weapons".

Jarba offered the 11 nations represented in the Friends of Syria core group a list of 10 proposed targets.

They included the Mezze Military Airport on the western outskirts of Damascus, the Qutaifa missile base north of the city and compounds of the Fourth Mechanised Division, a elite unit headed by Assad's feared brother Maher and composed mainly of members of his Alawite minority sect.

"GET TEAM READY" FOR TALKS

The Friends of Syria core group comprises the United States, Britain, France, Italy, Germany, Turkey, Saudi Arabia, Egypt, Jordan, the United Arab Emirates and Qatar.

U.N. experts trying to establish what exactly happened in the attack were finally able to cross the frontline on Monday to see survivors - despite being shot at in government-held territory. But they put off a second visit until Wednesday.

"The Americans are tying any military action to the chemical weapons issue. But the message is clear; they expect the strike to be strong enough to force Assad to go to Geneva and accept a transitional government with full authority," a Syrian opposition figure said.

"The message to the opposition was to get a team ready for Geneva, and be prepared for the possibility of a transition. But we must also be ready for the possibility of the collapse of the regime. If the strike ends up to be crippling, and if they hit the symbols of the regime's military power in Damascus it could collapse," the source said.

The sources said the meeting was planned before the suspected nerve gas attack on the Damascus suburbs, and was originally meant to discuss preparations for the proposed U.S.- and Russian-sponsored Geneva peace conference, which has been repeatedly put off.

Jarba said this month the coalition welcomed participating in Geneva without conditions, but it still expected the meeting to result in a transition that would remove Assad and his top aides from power.

Assad's foreign minister, Walid Moualem, said in June the authorities were ready to form a broad-based government of national unity, but they would not "head to Geneva to hand over power to another side", in an indication that Assad was not planning to give up control of the country.

(Reporting by Khaled Oweis, Writing by William Maclean; Editing by Alistair Lyon)